66851705 has 4 divisors (see below), whose sum is σ = 80222052. Its totient is φ = 53481360.

The previous prime is 66851693. The next prime is 66851723. The reversal of 66851705 is 50715866.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33547264 + 33304441 = 5792^2 + 5771^2 .

It is not a de Polignac number, because 66851705 - 2¹² = 66847609 is a prime.

It is a super-2 number, since 2×66851705² = 8938300922814050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6685166 + ... + 6685175.

It is an arithmetic number, because the mean of its divisors is an integer number (20055513).

Almost surely, 2^66851705 is an apocalyptic number.

It is an amenable number.

66851705 is a deficient number, since it is larger than the sum of its proper divisors (13370347).

66851705 is a wasteful number, since it uses less digits than its factorization.

66851705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13370346.

The product of its (nonzero) digits is 50400, while the sum is 38.

The square root of 66851705 is about 8176.2891949833. The cubic root of 66851705 is about 405.8549333298.

It can be divided in two parts, 6685 and 1705, that multiplied together give a triangular number (11397925 = T₄₇₇₄).

The spelling of 66851705 in words is "sixty-six million, eight hundred fifty-one thousand, seven hundred five".